As everyone here has stated it all comes down to whether you feel “this is the one!”
On my first visit to the store, I arrived just an hour before closing time after a drive in horrible traffic that took an hour longer than I expected. I was able to inspect the bass and verify everything worked and it was in amazing condition for its age (I'd call it "like new" except for one tiny finish ding). I only got to play it for a little while through an amp that was really not ideal (they plugged it into a little Fender Rumble combo sitting on the floor, what were they thinking? Probably that it was almost closing time and they didn't want to mess around with amps). I didn't have enough opportunity to really get to know it. Even so, I drove home (in more horrible traffic) wondering why it wasn't in my car.
This morning, I had a much easier drive, no time pressure, and they set me up with a more suitable rig (Aguilar head, Bergantino cab). I quickly found that I had something special in my hands. Is it "the one"? (In the Alembic world, is there ever just one?) I don't know; for now it's enough to say I'm very glad this bass came home with me. I'll post some more detailed comments and pictures in Showcase later.
Thanks to all the people who shared their advice and knowledge!
Okay, time to head off for a little summer jam with some of my bandmates....